The present invention relates generally to a particulate material densification system and, more particularly, to a vacuum-assisted system for forming bulk particulate material into a desired bulk form with minimal fibrous lumps and transferring the bulk material downstream for packaging.
Various devices have been proposed for shaping and packaging particulate material into a bulk form. Certain devices first compress the material into a bulk form and ram-direct the bulk into a preformed plastic bag. One problem with these devices is that the movement of the material bulk from one station to the other dislodges portions of the material from the previously shaped bulk, particularly at the corners thereof. This material separation can occur during ram induced transport particularly when directed through a downstream chamber such that friction arises. The resulting friction dislodges particulates from the material bulk, particularly at the corners thereof and forms fibrous lumps of material. Fibrous lumps in the particulate material cause an uneven material bulk, which precludes easy palletization and unnecessary waste of the particulate material.
While the packaging system shown in U.S. Pat. No. 5,943,846, granted to this inventor, solves many of the above mentioned problems, a system which provides an optimally densified material bulk which minimizes or even precludes fibrous lumps therein is still needed.
In response thereto, the present invention provides a system for vacuum-assisted densification of particulate material which comprises a vertical compression tower having walls and a top. A compression chamber having a series of sides and open upper and lower ends is reciprocatively mounted to the tower with piston/cylinder assemblies. A ram assembly is mounted to the top of the tower and extends downwardly through the chamber. The ram assembly includes a piston/cylinder assembly having a compression plate attached to a rod thereof for extension through the chamber.
The system also includes a conveyor assembly positioned below the tower and having a perforated conveyor belt extending thereabout. The chamber is selectably extendable between a first position displaced from the conveyor assembly and a second position adjacent the conveyor assembly. The conveyor assembly includes an air chamber that is coupled to a vacuum blower such that air within the chamber may be evacuated through the perforated conveyor belt when the chamber is in the second position.
Accordingly, particulate material can be drawn into the compression chamber and onto the conveyor belt when the compression chamber is lowered to its second position. As air is withdrawn therefrom through the perforated conveyor belt, the particulate material is compressed into bulk form upon the conveyor belt. The ram assembly is then extended to further compress the particulate material into bulk form. The chamber then returns to a position displaced from the conveyor assembly and an operation of the conveyor assembly conveys the bulk to a downstream recompression assembly.
The recompression assembly includes a second conveyor assembly horizontally adjacent the first conveyor assembly for receiving the material bulk. A third conveyor assembly is vertically displaced from the second conveyor assembly and material bulk. The third conveyor assembly pivots as the bulk is conveyed downstream by the second conveyor assembly such that the downstream ends of the second and third conveyors converge a predetermined amount to again compress the bulk. The material bulk is conveyed into a bag immediately upon recompression.
The second and third conveyor assemblies each include a conveyor belt having a fixed length which operates in a downstream direction for urging the material bulk downstream and then operates in an upstream direction before receiving another bulk from the first conveyor assembly. Accordingly, the inefficient or inaccurate tracking common to continuous conveyor belts is minimized or even precluded.
Therefore, it is a general object of this invention to provide a system for compressing particulate material into bulk form which uses negative air pressure to draw particulate material into a compression chamber.
Another object of this invention is to provide a system, as aforesaid, which utilizes a reciprocating compression chamber and a reciprocating ram assembly.
Still another object of this invention is to provide a system, as aforesaid, in which the open lower end of the compression chamber is closed upon lowering the chamber to bear against a conveyor assembly.
Yet another object of this invention is to provide a system, as aforesaid, which first compresses particulate material by evacuating air from the compression chamber.
A still further object of this invention is to provide a system, as aforesaid, which evacuates air from the air chamber through a perforated conveyor belt.
A particular object of this invention is to provide a system, as aforesaid, which diminishes the separation of the particulate material from the material bulk.
Another particular object of this invention is to provide a system, as aforesaid, which diminishes the production of fibrous lumps in the material bulk.
A further object of this invention is to provide a system, as aforesaid, in which the compression chamber retracts from the conveyor assembly after a material bulk is compressed by the ram assembly.
A still further object of this invention is to provide a system, as aforesaid, wherein the height of the material bulk can be regulated thereby providing for packaging weight modifications without deviance from the optimum length and width requirements necessary for palletization.
Another object of this invention is to provide a system, as aforesaid, which recompresses the material bulk as the material bulk is conveyed downstream of the compression chamber for packaging.
Still another object of this invention is to provide a system, as aforesaid, having a pair of conveyor assemblies which incrementally recompresses the material bulk as it is conveyed downstream of the compression chamber.
Yet another object of this invention is to provide a system, as aforesaid, in which the pair of recompression conveyor assemblies include non-continuous conveyor belts.
Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.